before_all can not intercept http processing use env.redirect "new_path"

Question

before_all can not intercept http processing use env.redirect "new_path"

zw963 opened this issue 2 years ago · comments

Description

Following is sample code:

before_all do |env|
  next if env.request.path == path.sign_in

  auth_token = env.session.string?("auth_token")
  
  current_user = User.get_user_by_auth_token(auth_token) # <============= this will return nil because not login

  if current_user.nil?
    puts "1"*100
    env.redirect path.sign_in                            # <============== what we expected is redirect to "/auth/login-in" instead
	puts "2"*100
    next
  else
    env.session.string("current_user_open_id", current_user.open_id)
  end
end

get "/" do |env|
  puts "3"*100
  open_id = env.session.string("current_user_open_id") # <================= but code come here, which cause exception.
  
  current_user = UserQuery.new.open_id(open_id).first

  render_use_layout "home.ecr"
end

get "/auth/sign-in" do
  errors = [] of String
  render_use_layout "auth/sign_in.ecr"
end

Expected behavior: [What you expect to happen]

When i visit 127.0.0.1:3000, because current_user = User.get_user_by_auth_token(auth_token) return nil,
i expect kemal redirect to "/auth/login-in" env.redirect path.sign_in; next

Actual behavior: [What actually happens]

please check log like this:

[development] Kemal is ready to lead at http://0.0.0.0:3000
1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111
2222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222
3333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333
Exception: Missing hash key: "93080ff27482881cd7f518835e52f16b" (KeyError)
  from /usr/share/crystal/src/hash.cr:1077:11 in '[]'
  from lib/kemal-session/src/kemal-session/engines/memory.cr:144:7 in 'string'
  from lib/kemal-session/src/kemal-session/engine.cr:82:5 in 'string'
  from src/test_project.cr:40:3 in '->'
  from lib/kemal/src/kemal/route.cr:12:26 in '->'
  from lib/kemal/src/kemal/route_handler.cr:49:39 in 'process_request'
  from lib/kemal/src/kemal/route_handler.cr:17:7 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/websocket_handler.cr:13:14 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/filter_handler.cr:21:7 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/static_file_handler.cr:5:14 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/exception_handler.cr:8:7 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/log_handler.cr:8:37 in 'call'
  from /usr/share/crystal/src/http/server/handler.cr:28:7 in 'call_next'
  from lib/kemal/src/kemal/init_handler.cr:12:7 in 'call'
  from /usr/share/crystal/src/http/server/request_processor.cr:51:11 in 'process'
  from /usr/share/crystal/src/http/server.cr:515:5 in 'handle_client'
  from /usr/share/crystal/src/http/server.cr:468:13 in '->'
  from /usr/share/crystal/src/fiber.cr:146:11 in 'run'
  from /usr/share/crystal/src/fiber.cr:98:34 in '->'
  from ???

the code in "/" still running, the exception raise because open_id = env.session.string("current_user_open_id")
visit not-exists key.

But, the issue is, this should not happen, it should redirect to "/auth/login-in" instead, right?

Versions

Crystal 1.50dev, kemal master latest.

Serdar Dogruyol - Sedo セド · Answer 1 · Wed Jun 22 2022 16:21:21 GMT+0800 (China Standard Time)

I think it's because of the next in the following, it breaks from if block and runs into the else condition

if current_user.nil?
    puts "1"*100
    env.redirect path.sign_in                            # <============== what we expected is redirect to "/auth/login-in" instead
	puts "2"*100
    next
  else

can you remove the nextand try again?

Billy.Zheng · Answer 2 · Wed Jun 22 2022 19:13:13 GMT+0800 (China Standard Time)

can you remove the nextand try again?

Sorry, remove next not work. the log is same when i visit "/"

[development] Kemal is ready to lead at http://0.0.0.0:3000
1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111
2222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222
3333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333
Exception: Missing hash key: "current_user_open_id" (KeyError)

Billy.Zheng · Answer 3 · Tue Jun 28 2022 01:22:27 GMT+0800 (China Standard Time)

Hi, @sdogruyol , i quite sure, env.redirect not work in before_all do block.

anyway, i need one place to all request to ensure current_user is exists, if this feature
not work, it quite hard to write DRY code.

Billy.Zheng · Answer 4 · Tue Jun 28 2022 02:01:53 GMT+0800 (China Standard Time)

Hi, i found why this issue happen.

Following is my before_all code

before_all do |env|
  next if env.request.path == path.sign_in

  current_user = User.get_user_by_auth_token(env.session.string?("auth_token"))

  if current_user.nil?
      env.redirect path.sign_in
    next
  else
      env.set "current_user", current_user
  end
end

Following is my router block

    get path.license_index do |env|
      current_user = env.get("current_user").as(User)

      licenses = LicenseQuery.new
    
      render_with_current_user("license/index.ecr")
    end

When i request path.license_index, at first, will retrieve current_user in before_all block.

We assume current case, current_user is nil, so, code env.redirect path.sign_in will run.

The really wired things is, before env.redirect really happen, the request handle process still wil go into
router block, env.get("current_user").as(User) will raise Missing hash key: "current_user" (KeyError) in
this case, because i never set it in before_all.

so, why this issue is happen is discovered, how to fix that? maybe i do things wrong way?

Anyway, i don't think we should do env.get?("current_user") check in my request block is useful.
because if i need check it, i really don't need before_all!

What i expected just is, redirect early in before_all call.

But, for now, before_all just is a place do some common things, but still continue.

I guess it caused by lazy? as describe by following

The Filter middleware is lazily added as soon as a call to after_X or before_X is made. 
It will not even be instantiated unless a call to after_X or before_X is mad

Chao Yang · Answer 5 · Tue Jun 28 2022 11:00:48 GMT+0800 (China Standard Time)

@zw963 I think you would want to close the response immediately after redirection.

if current_user.nil?
    puts "1"*100
    env.redirect path.sign_in                            # <============== what we expected is redirect to "/auth/login-in" instead
    env.response.close
    puts "2"*100
    next
  else
    env.session.string("current_user_open_id", current_user.open_id)
  end

@sdogruyol I think it makes sense to close the response inside of the HTTP::Server::Context#redirect method, better to make it an optional parameter:

    def redirect(url : String, status_code : Int32 = 302, *, body : String? = nil, close : Bool = true)
      @response.headers.add "Location", url
      @response.status_code = status_code
      @response.print(body) if body
      @response.close if close
    end

Even with this, it would still go through all before filters, it only stops at the beginning of Kemal::RouteHandler#process_request because it short circuits if the response is already closed.

Maybe we can add something similar to HTTP::StaticFileHandler's fallthrough option to filters.

Billy.Zheng · Answer 6 · Tue Jun 28 2022 12:28:25 GMT+0800 (China Standard Time)

@zw963 I think you would want to close the response immediately after redirection.

Yes, you are right.

Billy.Zheng · Answer 7 · Thu Jun 30 2022 21:32:02 GMT+0800 (China Standard Time)

Cool, my issue is solved! quite perfect.

before this, there is no easy way to use setted env in request handler.

e.g.

get path.home_index do |env|
  current_user = env.get("current_user").as(User)
  # ...
end

When i try to visit path.home_index directly without login in, will raise exception
because no "current_user" key get set before.

even, after i change to current_user = env.get?("current_user").as(User), it still not work.
because raise exception: " Exception: cast from Nil to User failed".

I really don't want add a if/else again for make current_user always work, even, i have done it in before_all.

Now, it works like a charm!!

Thanks for @sdogruyol , @cyangle , and all.

Billy.Zheng · Answer 8 · Thu Jun 30 2022 21:32:42 GMT+0800 (China Standard Time)

Do we consider release 1.1.3?

Serdar Dogruyol - Sedo セド · Answer 9 · Thu Jun 30 2022 21:43:48 GMT+0800 (China Standard Time)

@zw963 I'll release 1.2.0 with Crystal 1.5.0 👍

Billy.Zheng · Answer 10 · Thu Jun 30 2022 23:54:10 GMT+0800 (China Standard Time)

I'll release 1.2.0 with Crystal 1.5.0

Okay, that soulds reasonable, anyway, some default behavior in before_filter was changed.

Billy.Zheng · Answer 11 · Thu Jul 07 2022 15:52:49 GMT+0800 (China Standard Time)

@zw963 I'll release 1.2.0 with Crystal 1.5.0 +1

Forget to release 1.2.0 ? 😄

Serdar Dogruyol - Sedo セド · Answer 12 · Thu Jul 07 2022 16:52:58 GMT+0800 (China Standard Time)

Haha no @zw963 thanks for the ping 👍 I'll cut a release soon 🎉

Serdar Dogruyol - Sedo セド · Answer 13 · Thu Jul 07 2022 17:04:17 GMT+0800 (China Standard Time)

@zw963 there you go https://github.com/kemalcr/kemal/releases/tag/v1.2.0